An apparatus for processing materials, such as food materials which are to be blended or mixed therein, for example, often utilizes a mechanically rotating shaft for rotating a suitable blending or mixing mechanism, e.g. agitator blades, attached thereto. The shaft must be sealed, often at both ends thereof, against leakage of such materials. Such leakage is particularly a problem when using fine powdered food materials, for example, and/or where a slight misalignment of the shaft exists which can cause shaft run out up to as high as 1/8 inch in some types of apparatus.
The surfaces of such seal structures tend to become clogged with the food materials involved and require frequent maintenance and cleaning thereof so as to maintain acceptable sanitary operating conditions and to prevent unacceptable leakage of materials during operation of the apparatus. Up to now, conventional sealing structures using packing materials normally must be disassembled and the components thereof cleaned separately, usually manually. The packing used in the seal structure usually tends to deteriorate and must be replaced. The overall structure must then be re-assembled for use. Such maintenance and cleaning is not only time consuming but it can also increase the costs of operation, due both to the labor required as well as to the costs of the replacement packing material.
It is desirable to devise a sealing structure which can be thoroughly and consistently cleaned in place without disassembly thereof. Such a cleaning technique should be readily and conveniently usable by an operator and should be capable of being easily activated to provide an automatic cleaning operation whenever desired. While there may be an initial increase in cost in providing such an in-place cleaning structure, the overall operating costs, over the useful life of the apparatus, in time, labor, and materials can be considerably reduced.